A spindle motor performs the function of rotating a disk to enable an optical pickup which linearly reciprocates in an optical disk drive (ODD) to read data recorded on the disk. A slim-type spindle motor used for a notebook is installed with a clamping device for supporting the disk.
Generally, an apparatus for clamping disk (hereinafter referred to as “disk clamping apparatus”) includes a clamp body, claws formed at a lateral surface of the clamp body to apply pressure to an inner circumference of a disk and to match the center of the disk with that of a rotation shaft, and an arm applying pressure to the disk to prevent the disk from being disengaged.
The conventional disk clamping apparatus suffers from disadvantages in that a force applied to an inner circumference of a disk by claws is almost the same as or greater than a force applied to the disk by an arm, whereby even though the claws apply pressure to the claws, a rotation center of the disk is eccentrically deviated from a rotation center of a rotation shaft.
In a case the force applied to the disk by the arm is the same as or greater than the force applied to the disk by the claws, a rotation center of the disk relative to a rotation center of the rotation shaft is eccentricated by approximately 80 μm to 120 μm.
In a case the rotation center of the disk relative to the rotation center of the rotation shaft is eccentrically disengaged by approximately 80 μm to 120 μm, the disk eccentrically rotates relative to the rotation shaft to disable an accurate recording of data on a designated position of the disk. Another disadvantage is that in a case the disk eccentrically rotates relative to the rotation shaft, the data cannot be read from a particular position of the disk.